how to create a trigger for ifoperstatus of routers interfaces

[barry1946]

I have created manual snmp items for ifoperstatus of my router (ZTE zxr10)
but I don't know how to choose a trigger expression for it?
I checked this topic in forum:

https://www.zabbix.com/forum/showthread.php?t=25759

but I didn't get how to do it?
my question is that if I have to create a manual expression for this and if so how to do this because I have no idea about it.
please guide me through this of how to create a working trigger for this to check if an interface goes down I receive some alarm in my zabbix 2.2
thank you indeed

[aib]

For example, check the Template SNMP Interfaces.
Under Discovery rule -> Trigger prototype you can see the prototype of trigger which is switch when the Operational Status of interface is changes.

[barry1946]

thanks for that.
what about a trigger that creates an alarm while the interface is down an clears while it goes up again?

[aib]

Operational Status (usually) has three different states:
- UP
- DOWN
- Administratively down

And the trigger from Template is controlling the change of state.
Using your words "a trigger creates an alarm while the interface is down an clears while it goes up again"